.TH socket_connect6 3
.SH NAME
socket_connect6 \- attempt to make a TCP connection
.SH SYNTAX
.B #include <libowfat/socket.h>

int \fBsocket_connect6\fP(int \fIs\fR, const char \fIip\fR[16],
                    uint16 \fIport\fR,uint32 \fIscope_id\fR);
.SH DESCRIPTION
socket_connect6 attempts to make a connection from TCP socket \fIs\fR to
TCP port \fIport\fR on IP address \fIip\fR.

The meaning of \fIscope_id\fR is dependent on the implementation and
IPv6 IP.  On link-local IPv6 addresses it specifies the outgoing
interface index.  The name (e.g. "eth0") for a given interface index can
be queried with getifname.  \fIscope_id\fR should normally be set to 0.

socket_connect6 may return
.sp 1
.IP \(bu
0, to indicate that the connection succeeded (and succeeded immediately,
if the socket is non-blocking)
.IP \(bu
-1, setting errno to error_inprogress or error_wouldblock, to indicate
that the socket is non-blocking
.IP \(bu
-1, setting errno to something else, to indicate that the connection
failed (and failed immediately, if the socket is non-blocking).
.PP

When a background connection succeeds or fails, \fIs\fR becomes
writable; you can use socket_connected to see whether the connection
succeeded.  If the connection failed, socket_connected returns 0,
setting errno appropriately.

Once a TCP socket is connected, you can use the read and write
system calls to transmit data.

You can call socket_connect6 without calling socket_bind6.  This has the
effect as first calling socket_bind6 with IP address :: and port 0.

.SH EXAMPLE
  #include <libowfat/socket.h>

  int \fIs\fR;
  char \fIip\fR[16];
  uint16 \fIp\fR;

  \fIs\fR = socket_tcp6();
  socket_bind6(s,ip,p);
  socket_connect6(s,ip,p,0);

.SH "SEE ALSO"
socket_connect4(3), socket_fastopen_connect6(3), socket_getifname(3)
